So-called two-substance nozzles are already known in various constructions. A liquid and a gaseous medium are for example delivered under pressure to these nozzles, and these media are mixed with one another inside a mixing chamber. When such nozzles are used to discharge plant protectives, additional air is generally used only in order to increase the speed of the particles or droplets or to refine the drop spectrum, i.e. in order to reduce the mean drop diameter. Due to a relatively high consumption of additional air and due to the necessity of a pressure generator such nozzle systems are technically relatively costly and not very practical. In addition, the air pressure influences the quantity of liquid sprayed out, so that the technical expenditure is further increased by arrangements for regulating the quantity or keeping the quantity constant.
For discharging plant protectives injector nozzles with automatic air intake are also known, above all in the case of small hand-operated devices. The advantage of such injector nozzles lies in the unproblematic flow regulation by way of the fluid pressure, in a reduced susceptibility to wind--with regard to the discharge of plant protectives--due to a greatly increased drop diameter, and in an improvement of the coating structure on the target area, since when the air-filled drops strike for example the plant surfaces they burst, so that larger wetting surfaces are achieved with the same volume of liquid. Due to the expansion of the compressed air or gas particles when leaving the nozzle, the drops undergo an additional acceleration, which allows an improved penetration of the target stocks. However, an inhomogeneity of the liquid/air mixture before the nozzle outlet orifice has proved a disadvantage. It results in strong pulsations in the delivery of the liquid so that extremely varied drop sizes and strong fluctuations in the distribution characteristic and in the discharge of the liquid/air mixture occur in the micro range at the nozzle outlet orifice.
The object of the invention, therefore, is to create an injector nozzle that retains the previously described advantages of the known constructions and has a relatively simple design, distinguished by a particularly high uniformity of the drop sizes and a distribution characteristic of these liquid drops which is largely free of fluctuations.